Due to recent advancements in drilling technology that employ hydraulic fracturing or “fracking”, it is now possible to extract natural gas and oil deposits from shale rock layers deep within the earth that were once unreachable with conventional technologies. Fracking is the process that injects a highly pressurized fracking fluid, a major component being fracking sand, into the shale area to create new channels within the rock for natural gas or oil to be extracted at higher than traditional rates. With the advent of fracking and the increase in demand for fracking sand, new methods of transporting this very specialized sand is required.
Conventionally, raw sand is transported over the road by steel dump trucks and end dump or belly dump style semi-trailers. These conventional sand transport methods load and dump sand in bulk and do not allow for any type of metering capabilities, especially during the unloading process. Fracking sand is a very specialized type of sand, wherein raw sand is processed and dried to meet specific characteristics and properties needed in the hydraulic fracturing process. Once processed, the sand must normally be transported to a railroad or truck terminal for further transport to the often remote drilling fields. Since one common and efficient method of transferring sand from a truck or trailer to a train car is by means of a conveyor system, metering the unloading of fracking sand is required so that the conveyor system is not overwhelmed by a sudden influx of sand being dumped upon it.
In the attempt to be able to meter fracking sand, companies have tried to use dual hopper grain trailers which contain two hoppers and small bottom gates that are no more than two feet by two feet in area, but due to the abrasive and corrosive properties of the fracking sand, these trailers quickly deteriorate and have extreme maintenance costs. Though a dual hopper grain trailer has a hopper door opening that works well for low moisture content grain, it is undersized for unloading raw wet sand, so it cannot be used as a dual purpose trailer for both wet raw sand and dry fracking sand.
It is an object of the invention to provide a sand trailer with an oversized hopper door opening to allow raw sand, particularly raw wet sand, to be quickly and easily unloaded.
It is a further object of the invention to provide a sand trailer with the ability to control the flow rate of the fracking sand exiting the sand trailer.